Invasive Species Management

Agriculture information

Noxious Weed Awareness

Jeffco Invasive Species Management is partnering with the Colorado Department of Agriculture and The Colorado Weed Management Association to raise awareness about the impacts and the need to control noxious weeds.

Learn what you can do.

Adult Emerald Ash Borer beetle.

Emerald Ash Borer

Jeffco Invasive Species Management and Jeffco CSU Extension have partnered to promote EAB awareness within our county. 

Information is available on our EAB pages that will assist you with understanding the issue, how to identify EAB, how to determine if you may have it, and how to plan for managing it.

Japanese beetle adult on leaf.

2023 Japanese Beetle Citizen Science Project

Landowners may enter their information to help us better understand the Japanese beetle populations along the Front Range.  

We will be using our online map to track early emergence and document the preferred Colorado hosts.

Reporting Form

Orange hawkweed flowerhead.

Need Noxious Weed Advice?

  • For properties within unincorporated Jeffco - We are able to answer calls and questions. Our hours are Mon -Thur 6:30 am - 5 pm.  Please phone ahead to make an appointment.  303-271-5989
  • For properties within city limits please contact your city's weed authority.  Local Contacts

Weed of the Month

Each month we will feature a noxious weed to help landowners identify weeds they may encounter on their property.


December 2023

Arundo (aka Giant Reed)

Arundo donax

Giant reed is a perennial grass that can grow to 25+ feet tall.  Originally imported to the US as an erosion control and horticultural plant in the 1800s, it has escaped and moved into many riparian areas in the west.  It is native to the Mediterranean region and eastern Asia.

It spreads by rhizomes and stem nodes and can form large clumps resembling bamboo.  It grows in full sun and in lightly shaded areas and is very drought tolerant.

The leaves can be 2 inches wide and up to 36 inches long.  Stems are ¼ -2 inches wide.

Its distinctive auricles clasp the stem.  The ligules are large and papery with small hairs along the margin. 

The flowers are arranged in a large plume 1-2 feet long.  Within North America, it is not believed that the seeds are viable. 

Giant reed forms huge colonies along waterways.  It disrupts the water flow, increases sedimentation, and changes the structure of water channels that can lead to erosion.  Dead and dry stands can pose a fire hazard. 

Colorado has less than 500 known locations and this List A noxious weed needs to be completely eliminated.  Because it easily spreads by plant fragments removal is not an option.  Use of a systemic herbicide will give the best control.

Control includes treating with herbicide .  Visit us at for more information.


Colorado Weed Management Association  Noxious Weeds of Colorado 14th Edition


Alicia Doran


Weed of the Month is a joint effort between Jefferson County Invasive Species Management, CWMA, and Archuleta County.

LG_NoxWeed_2020_cover Opens in new window

A Landowner's Guide - Developing a Noxious Weed Management Plan

We developed this guide to assist landowners.  The information provides steps to develop a management plan for properties that have noxious weeds.

Download your copy